Life cycle assessment of constructed wetlands: measuring their contribution to sustainable development

Life cycle thinking has led to the development of a series of methodologies that evaluate the sustainability of any process, product, or activity, considering the three aspects of sustainable development: the environmental, economic, and social pillars. These methodologies called the (Environmental) Life Cycle Assessment, the Social Life Cycle Assessment and the Life Cycle Costing, have the peculiarity to consider the whole life cycle of a product or process, from the extraction of raw materials to their end of life. At the same time, sustainable development has led to the strengthening of disciplines and novel technologies such as circular bioeconomy, industrial ecology, and nature-based solutions. In this context, constructed wetlands have been gaining popularity since they are a low-cost alternative for urban and industrial wastewater treatment in small communities. The performed life cycle assessments of these technologies have shown that, regardless of the model, configuration, or type of waste treated, they have low environmental impacts compared with conventional solutions (e.g., activated sludge system) due to low energy requirements, no chemicals consumption, and avoidance of off-site management and transportation practices. In terms of costs, constructed wetlands can drastically reduce the costs associated with wastewater treatment and management. However, more efforts should be made in order to define the social benefits of this technology (e.g., local employment generation, landscape improvement) and the quality of the recovered resources (e.g., treated water, fertilizer).